Is the decadal variability in the tropical Atlantic a precursor to the NAO?

• Published in: Annales Geophysicae
• Main Authors: I. Wainer, J. Servain, G. Clauzet
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2008
• Subjects: Science; Q; Physics; QC1-999; Geophysics. Cosmic physics; QC801-809; North Atlantic; North Atlantic oscillation
• Online Access: https://doi.org/10.5194/angeo-26-4075-2008; https://doaj.org/article/5c1bd952f9fd4504a5acc05759c317f8

In the past two decades climate research in the tropical Atlantic with respect to the inter-hemispheric gradient of sea surface temperature (SST) emphasized the predominance of decadal-scale variability. Our results show that this mode of variability is prevalent only for part of the last 130-years record (the 1880s, the 1920s and, especially, the 1970s). There is a lag of a few months between the decadal variations of the inter-hemispheric gradient of SST and the decadal variability of the North Atlantic Oscillation (NAO). This seems to indicate that the 10-year variability first develops in the tropics and then propagates polewards. The inter-hemispheric gradient of SST mode should be thought as episodic and not as a periodic oscillation.